Division Haptophyta Hibberd Class Prymnesiophyceae D.J. Hibberd (1976) see Class Coccolithophyceae Rothm. (1951) Subclass Prymnesiophycidae (D.J. Hibberd) Cavalier-Sm. (1986) see Class Prymnesiophyceae D.J. Hibberd (1976) "Heterococcoliths" "Muroliths" Order Zygodiscales Young & Bown (1997) Family Helicosphaeraceae Black (1971)